Storage-stable nitrogen-zinc foliar spray compositions

Abstract

Storage-stable fertilizer compositions comprising aqueous solutions of zinc nitrate, ammonium nitrate and optionally, urea, in minor amounts, are provided.

We claim: 
     
       1. A composition comprising a storage-stable fertilizer solution of pH below about 5 consisting essentially of water, about 8% to 20%, by weight, of zinc nitrate solute, about 18% to 36%, by weight, of ammonium nitrate solute and urea solute in an amount from 0 up to about 6%, by weight, of the composition, said fertilizer solution having an ammonium nitrate to urea weight ratio of at least about 3 to 1 and a nitrogen to zinc weight ration of between about 1 to 1 and 8 to 1. 
     
     
       2. The composition of claim 1 additionally containing up to about 1,000 parts, by weight, of water, per part of the composition, said composition being capable of being applied as a foliar spray fertilizer. 
     
     
       3. The composition of claim 1, further characterized by having a salt-out temperature below about 32° F. 
     
     
       4. The composition of claim 1 having a pH of between about 3.5 and 5 additionally containing a water-soluble thiosulfate compound in an amount sufficient to inhibit corrosion to carbon steel. 
     
     
       5. The composition of claim 1 wherein the zinc nitrate is present in an amount between about 12% and 18%, by weight, the ammonium nitrate is present in an amount between about 25% and 35%, by weight, the urea is present in an amount from 0 up tp about 4%, by weight of the composition, and the pH of the fertilizer solution is between about 3.7 and 4.5, said fertilizer solution having an ammonium nitrate to urea weight ration of between 5 to 1 and 15 to 1 and a nitrogen to zinc weight ratio of between about 2 to 1 and 6 to 1. 
     
     
       6. The composition of claim 5 additionally containing up to about 200 parts, by weight, of water, per part of the composition, said composition being capable of being applied as a foliar spray fertilizer. 
     
     
       7. The composition of claim 5, further characterized by having a salt-out temperature below about 28° F. 
     
     
       8. The composition of claim 5, additionally containing a water soluble thiosulfate compound selected from the group consisting of ammonium thiosulfate, sodium thiosulfate and potassium thiosulfate in an amount sufficient to inhibit corrosion to carbon steel. 
     
     
       9. The composition of claim 1 wherein the zinc nitrate is present in an amount between about 14% and 16%, by weight, the ammonium nitrate is present in an amount between about 28% and 32%, by weight, and the urea is present in an amount up to about 3%, by weight, of the composition, and the pH of the fertilizer solution is between about 3.7 and 4.5, said composition being substantially free of zinc-containing precipitates after storage at temperatures of at least about 85° F. for a period of four months. 
     
     
       10. The composition of claim 9 additionally containing a water-soluble thiosulfate compound selected from the group consisting of ammonium thiosulfate, sodium thiosulfate and potassium thiosulfate present in an amount between about 0.1 and 0.5%, by weight, of the composition. 
     
     
       11. The composition of claim 10 additionally containing between about 80 and 200 parts, by weight, of water, per part of the composition, said composition being capable of being applied as a foliar spray fertilizer. 
     
     
       12. The composition of claim 10 further characterized by having a salt-out temperature below about 28° F.